Television system and method



July 14, 1942. IL N, M ||QwE;| g-;.` 2,289,363

TELEVISION SYSTEM AND METHOD Filed March 27, 1940 SvSheets-Shee'd 1INVENTOR v TORNEY A'July 14 1942. v u. N. M. HowELLg 2,289,363

TELEVISIO SYSTEMA ND METHOD Filed March 27,-?'1940 s sheets-sheet 2*AMPI IEYING f STAGES INVENTOR i -ARNEY July 14, 1942- J. N. M. HowELLsv2,289,363 I v TELEVISION SYSTEM AND METHOD v Filed Marchv27, 1940 3Sheets-Sheet 3 Amun/ms l /j Y STAGES L? ,#72 lNvEN-roR I Patented14.1942

UNITED STATES PATENT OFFICE TELEVISION SYSTEM AND METHOD John N. M.Howells, Kittery, Maine Appiisunn March zi, 1940, serial No. 326,255*

' (ci. nas-7.1) Y

'11 claims.

f This invention` relates a television ysystem and method. Moreparticularly, the invention relates` to a television system whichemploys radio frequency carrier waves.

One of the objects of my invention is to provide a television systemhaving novel means for scanning and reproducingl scenes.

Another object of my invention is to provide highly compact randeiiicient television scanning and reproducing cells. r

A further object of my invention is to provide an improved televisionsystem whose parts shall be relatively inexpensive to manufacture andassemble, and which shall be simple to use .and

vshall transmit still or moving scenes with a high degree of delity.

Still another object of myinvention is to pro- `vide a novel televisiontransmitting system having a long transmission range.

Other objects cf this'invention will in part be obvious and in parthereinafter pointed out.

The invention accordingly consists in the features of construction,combinations of elements, and arrangement of parts which will beexemplilfled in the construction hereinafter described,

and of which the scope of application will be indicated in the claims.

i In` the accompanying drawings, in whichis shown one of the variouspossible embodiments of this invention,

, Fig, 1 is a plan view of a scanning cell constructed in accordancewith my invention and Fig. 6 is a perspective view of a laminar unit ofthe scanning cell shown in Fig. 1;,

Fig. '1 is a wiring diagram of a simple television transmitting circuitemployingvthe cell shown in Fig. 1; i y Fig. 8 is an elevationalschematic view of scanning apparatus employing iny scanning cell; Fig. 9is an enlarged sectional view taken along the line` 9--9 of Fig. 8;

Fig. 10 is a front view of the apparatus shown in Fig. 8; f

Fig. 1.1 is a wiring diagram of a television receiver employing areproducing cell embodying my invention;

Fig. 12 is an elevational schematic view of re producingapparatusemploying my reproducing cell; l

Fig. 13 is a front elevational view of the apparatus shown in Fig. 12;

Figs. 14 and 15 are sectional views through a reproducing cell embodyingmy invention and showing different portions of one of the laminarscanning cell comprising a plurality of closely spaced elementalVphoto-responsive areas P forming a narrow scanning line S-S. Each ofthese elemental areas is provided with means to associateacharacteristic frequency therewith. Such means may comprise a capacitiveor induc vtive reactance or both, electrically connected in a suitablemanner with each ofthe areas P and preferably-comprises a plurality oflaminar units, each including a complete oscillatory circuit and havingincorporated therewith an elemental photo-responsive area.

In Figs. 1` to 6 I have showna scanning cell 20, -l embodying myinvention, housed in a casing 2| The condensers 23 may be of any typeknown to the art and preferably comprise two ilat layers of metal foil25 and 26 separated by an insulating layer such as a mica sheet 21.Condensers of this type may be made extremely thin and are 40' readilyassembled into a compactcondenser block vsuch as shown in Fig. 1.

At the rear of each of the condensers 23 4I may provide a coil 28,whose` ends are' attached by i may frictionally engage and be supportedbythe insulating layers 24.

Each set of condensers 23 and coils 28 thus .i

connected forms an independent auxiliary circuit A (see Fig. 7) having afixed natural resonant Afrequency-which is a function of its inductiveand capacitive reactances. I suitably `adjust these circuit constants sothat each of the auxiliary circuits A-An has'a different resonant) radiofrefluency. V y

Although this adjustment may be made by sponsive areas P.

varying either or both the capacitance or inductance, I prefer to varythe capacitance only,

by changing the area of the condenser plates 25 and 26, as this methodwill permit standardization in the manufacture of the coils 28. The sizeand shape of the plates 25 and 26 may be readily changed so that asuitable resonant frequency may be assigned to each of the individualauxiliary circuits A-An before assembly of the condenser block. This maybe conveniently accomplished by reducing the height of the plates 25 and26.

The frequencies to which the various auxiliary circuits A--An aretunedshould be spread apart suiciently as, for example, kilocycles, sothat they may be readily segregated in a receiving circuit such as thathereinafter described without appreciable distortion.

I may also arrange the various condensers 23 and coils 28 in the housing2| so as to reduce inductive and capacitive coupling between the CFI tothe coils 28 across the full width of the 'scanning cell 28. n

All the auxiliary circuits A-An may be connected in parallel within thecell 20 as shown in Fig. '1. For. this purpose, I may provide Wires 36and 31'. The wire 36 may be directly connected to each of the condenserplates 26 and the wire 31 may be connected to each of the condenserplates 25 through a blocking resistor 49.

Suitable terminals 38, 38', 39, 40 and 4| may be provided on theexterior of the housing 2| for the tickler coil 35, the electrode 33 andthe wires- 36 and 31, respectively.

circuits A-An having neighboring frequencies and thus further reduce anytendency to distor the transmitted image.

order: 10,000; 10,120; 10,240; 10,360; 10,480; 10,600; 10,720; 10,840;10,960; 11,080; 11,200; 11,320; 10,010; 10,130--11,l90; 11,310; 11,430.

This arrangement of the auxiliary circuits and variation of the heightof the condenser plates and 26 will result in a stepped profile of thecondensers 23 in the condenser block such as vshown in Fig. 2.

Associated with each \condenser plate 25, I

may provide a narrow block 3| having a concave surface 32. The block 3|may be integrally formed with'the plate 25 as indicated in Fig. 6 andhas a! depth substantially equal to the depth of the condensers 23. Thegroove 32 is suitably provided 'with a thin layer 'of any `:yell knownphoto-responsiveA substance, such as potassium.

which emits electrons under the influence of light. to provide anelemental photo-responsive area P. iThe blocks 3| may be spaced fromeach other by an'extension 24 (see Fig. 5) of the mica sheet 24. Theextensions 24 are preferably concaved in the same manner as the blocks3| The elemental photo-responsive areas are aligned across the width ofthe scanning cell 20 vto form a narrow scanning line S-S.

An electrode 33 of ne wire, insulated lfrom the housing 2| and suitablysupported therein, is disposed over the scanning `line S-S transverselyof the blocks 3| and is adapted to receive electrons emitted from theelemental photo-re- A colorless transparent plate 34 is provided in thecovenplate 22 over the scanning line S-S.

Air may be evacuated from .the entire interior of the housing or onlythat portion thereof adjacent the blocks 3| in order tofacilitatepassage of electrons from the'photo-responsive areas P to thewire electrode 33.

A tickler coil 35 may also be provided within a multi-frequencyoscillator or an oscillator modulated by said plurality of frequencies.

In Fig. 7 I have illustrated a 'simple multifrequency oscillatingcircuit adapted to generate and transmit a plurality of frequencies byemploying a scanning cell 20 such as that described with reference toFigs. 1 to 6. The electrical symbols enclosed 'Within the dotted lineson said figure represent the elements contained in a scanning cell 20. I

The oscillating circuit may comprise a vacuum tube oscillator 42 whosefilament is heated by means of a low p. ,ential battery 44. The grid 45of the tube 42 is connected through a grid leak 4,6, terminal 40 andwire 36 to the` condenser plates 26 of each laminar unit. Each of theother condenser plates 25, which are directly connected with theirrespective associated elemental photo-responsive areas P, is connectedthrough its own resistor 49, wire 31 and terminal 4| to the negativebinding post of a high potential battery 41, thus maintaining a suitablenegative potential upon the photo-responsive areas. The electrode wire33 is maintained at a lower potential than the areas P by connectionthrough the terminal 39 to the filament 42.

Invorder to provide a feed-back from the plate for oscillation, thetickler coil 35 is connected through its terminals 38, 38 between thepositive binding post of the plate battery 41 and the plate 48 of thevacuum tube 42. f Suitable amplifying stages and an antenna systemarealso connected in the plate ycircuit in any'well known manner. 4

In the operation of the circuit illustrated in Fig. 7, when lightstrikes one of the elemental photo-responsive surfaces P associated withone of the auxiliary circuits A-An, an oscillating circuit will becompleted through said auxiliary circuit, -photo-responsive area,electrode 33, vacuum tube 42, tickler coil 35 and battery 41 in a manener well known in the art. As the return plate circuit to the filamentpasses through the elemental photo-responsive cells, the'amplitude ofthe oscillations generated at the frequency of the housing 2| anddisposed in close proximity 75 lations generated at any particularfrequency will therefore'be a function of the intensity of the lightfalling on the photo-responsive surface P associated with saidfrequency.

I also provide means to cause the frequency generated in any auxiliarycircuit, A-An, to only be modulated by the photo-responsive area Passociated with said circuit. Such means be transmitted by 'means of myimproved cell 2B, it is scanned in one direction in time and in theother direction by a complex radio frequency wave comprising a pluralityof different fixed radio frequencies and the amplitude of each frequencywill continually vary in accordance with the light tone value of the.corresponding eiemental areas of the scene being transmitted.

photo-responsive surface P not associated with it is almost whollydissipated by passage in series through two blocking resistances 49.

It will thus beseen that I have provided a pluralityobparallel auxiliaryoscillating circuits A-'' An having varied natural resonant frequencieswherein the. amplitude of the currentand' voltage flowing in eachcircuit is a function of the intensity of light falling on an elementalphoto- :responsive cell associated with that circuit.

As the scanning speed of a television transmitting system employing myinvention is 'relatively low, the carrierfrequencies generated by theauxiliary circuits may be of a relatively low order and will thereforehave a transmitting range which is limitedonly by the power of thesending station. A

I also provide means for segregating the several frequencies of thecomplex transmitted wave and resolving them into a visible image. Suchmeans It is apparent that lf other types of oscillating circuits areused other-,than that illustrated in Fig. 7, the elements andconnections within my scanning cell 20 may be altered, changed orincreased to conform to the features land requirements of suchalternative circuits without departing from the spirit of my invention.

My novel scanning cell 20 may be employed to scan'a scene with the aidof a suitable optical system either by moving the scanningcell relativeto the optical system or moving the optical system relative to thescanning cell or by a combination of both of these movements.

'In Figs. 8, 9 and 1 0 I have shown one form of apparatus `adapted toemploy my novel scanning cell in scanning a scene 5llvby rotating aplurality of identical scanning cells 25 relative vto a'iixed 4 opticalsystem 5l.

I may provide a disc 52 fixed at theend of a rotatingshaft 53 ofinsulating material. Equiducing cell Bil embodying my invention andhavinga construction essentially the same as that` distantly spacedapart adjacent the periphery of said disc, I may'dispose a `plurality ofscanning cells 20 having their scanning lines S-S identic'allyequidistantly and radially disposed relative to the shaft 53. The pathof travel of said scanning lines is suitably disposed relative to the-optical system'5l so that the scanning lines SS,

as they are rotated, will traverse an' image of the scene. vcast by theoptical system 5l on the scanning disc 52.

' Said shaft may be provided with a plurality of split rings 551, 552,55;',I 554, and 555 separated from each other by insulating sleeve's 54.Each of said rings may comprise a plurality of electrically conductivesectors SB equal in number to the number of scanning cells employed 'andseparated from each other by insulating sectors 51.'

, 35', 39, l0 and 4| of the cells 25 in the oscillating I tube circuitso that each of` the rotating scanf ning cells, while it scans thescene, will be inserted in thetransmitting circuit.

Thecells 2l should be spaced close enough to-I gether and the disc 52should be rotated at a sufficiently high speed to' maintain the illusionof continual vision' at the receiver as is well known in the art. 1

It will thus be seen that when apicture is to respect. to each otherwithin the casing. 6|. Il

comprises a plurality of closely spaced elemental light emitting areas-Lforming a narrow `reproducing line R-R. Each of these elemental areas isprovided with means to associate a characteristic frequency therewith.Such means may comprise a capacitive or inductive reactance or both,

electrically connected in a suitable manner with each of the lightemitting areas L and preferably comprises a plurality of laminar units,each including a-complete oscillatory circuit and having incorporatedtherewithan elemental light emitting area.

In Figs. 14 through 16 I have shown a reproshown and described in myscanning cell 20. Said reproducing cell may comprise a casing 6| having'a cover plate 62. Housed Within the casing are a,

plurality of condensers 63 of any well known type and preferablycomprising a pair of flat condenser plates 5l and 65 separated by asheet 65 of insulation, such as mica. The condensers 63 are electricallyinsulated from each other yby a sheet of insulation BLsuch as mica, andare closely packed together to form a condenser block. Each condenser 63is provided with a coil 68 which may be disposed at th `rear thereof andis connected thereto by leads 9 and 10, as indicated in Figs. 14.and 15.The coils 68 may frictionally engage and be supported by the insulatinglayers 61. v

Each set of condensers 63 and coils B8 thus connected forms anindependent auxiliary circuit B (see Fig. 11) having a fixed naturalresonantfrequencywhich is a function of its inductiveand capacitivereactances. I suitably adjust these circuit. constants so that each ofthe auxiliary .circuits B-'Bn inthe receiver has a natural frequencycorresponding to the freqencies generated by the Vmatching circuits*-The condensers 63 responding to the respective sending circuitsA-An,.occupy the same relative position with prefer to adjust thefrequencies of the auxiliary circuits BfBn by varying the size ofthecondenser plates 64 and 65 in the same mannerwas the plates 25 and'26 in the scanning cell 20.

Associated with each condenser plate 64 I provide suitable Vmeans forvisually indicating the strength of the currentinduced in each of theauxiliary circuits B-Bn. Such means may cornprise a pair'. of spacedarcuate terminals 1| and "I2 of which one terminal Il may be integrallyformed with the condenser plate 5l. The other terminals 12 may beconnected in parallel by a wire 13. The sets of terminals 1| and 12,associated with each of the auxiliary circuits B-Bn, have a depthsubstantially equal to the depth of the condensers 63 and are spacedfrom each other by means of extensions 61 of the mica sheets 61. Arubber insulating block 14 may also be disposed at the rear of each setof terminals 1| and 12 as shown in Fig. 15 and be suitably attachedthereto as, for example, by vulcanization. The extensions 61' arepreferably provided with a recess shaped to conform to the space betweenthe terminals 1| and 12.

It will thus be seen that I have provided a narrow reproducing line R-Rin the form of a trough 15 which is composed alternately of layers ofinsulation. 61- and aligned elemental lightemitting areas L comprisingpairs of terminals 1| and 12.

A colorless transparent plate 62 is disposed in the cover plate 12 overthe reproducing line R--R.

Air may be evacuated from the portion of the cell adjacent the trough'15 and a suitable gas introduced which will emit a substantially whiteluminous light when an alternating current'is passed therethrough, as iswell known to the art. r

A coil 16 may also be provided Within the housing 6I and disposed inclose proximity to the coils 68 across the full width of the reproducingcell 60.

Suitable terminals 11,111 and 18 may be provided on the exterior of thehousing 6I for the two ends of the coil 16 and the wire 13,respectively.

I may provide any suitable receiving circuit adapted to segregate theplurality of frequencies transmitted in accordance with my invention andactuate the light emitting areas L corresponding to the matchingenergized light P at the transmitter.

In Fig. 1l I have illustrated a simple receiving circuit employing areproducing cell 60 such as that described with reference to Figs. 14,15 and 416. The electrical symbols enclosed within the dotted lines onsaidiigure representI the elements contained in a reproducing cell 60. I

The receiving circuit comprises the usual amplifying stages which feedan energizing coil 16. The coils 68 of the auxiliary oscillatingcircuits B--Bn are inductively coupled with the energizing coil 16 sothat a high frequency alternating responsive areas lar to thedisposition of the wire electrode 33 inV within my reproducing cell 60may be altered, changed or increased to conform to the features andrequirements of such circuit, without departing from the spirit of myinvention.

In place of the terminals 1| and 12, I may provide other suitable lightemitting means such as a fluorescent layer suitably deposited on thevtransparent plate 62' and locally energized at circuits B-Bn. Thefluorescent layer may be located in the plate return circuit in a mannersimithe transmitter circuit of Fig. '7.

The mechanical apparatus, including the optical system, employed in atelevision receiver embodying my invention should be of the samecharacter as that used at the transmitting end. Accordingly, in theembodiment of my invention herein described, the mechanical apparatusmay comprise a disc 80 fixed to the end of a shaft 8| of insulatingmaterial whose rotation is syn',- chronized with the rotation of theshaft 53 a't the transmitter by any means well known in the art.

Mounted adjacent the periphery of the disc 80 are a plurality ofidentical reproducing cells 60 equal in number to the number of scanning'cells 20 used at the transmitter and having their reproducing lines R-Rangularly spaced and disthe same manner as the scanning lines S-S andshaft 53.

voltage will be induced in each of the auxiliary i circuits whosepotential is proportional to the amplitude of the matching frequencygenerated in the auxiliary transmitting circuitsl A--An. The voltagethus applied to the terminal 1| will create aluminous discharge betweenit and the grounded terminal 12 whose intensity is proportional 'to theamplitude of the matching frequency at the transmitter.

Many circuits such as, for example, simple, regenerative or oscillatingdetector circuits might be employed in place of the circuit shown inFig. 11 which use a reproducing cell comprising a plurality of elementallight emitting means each having a characteristic frequency associatedtherewith. If a feed-back oscillating circuit is employed, the terminals1I and 12.of my reproducing cell may be inserted in the plate Yreturncircuit in the same manner that the photo- Sectored split rings 821,822, and 82a, vsimilar to the split rings 55, may also be provided andseparated from each other by insulating sleeves 4cells 60 in thereceiver circuit while it isin position to reproduce a scene.

When a televised picture is reproduced by means of `my improvedcell,6|), the reproducing line R-R, connected in the receiving circuit,will appear as a single'line having a varying intensity of light alongits length corresponding to the varied intensity of the line of thescene being scanned by the complex radio frequency wave and as the lineR-R moves with the disc, it will reproduce the televised image, castingit by means of a -xed optical system 85 on a viewing screen 86.

. f My television system may also be employed to responsive areas P andWire electrode 33 are inserted in the transmitter circuit of Fig. 7.

If such alternative circuits are employed, it

transmit colored pictures by employing colored filter plates in place ofthe colorless cover plates 34 in successive scanning cells 20. Said lterplates may be colored in complementary colors as is well known in theart so that various scan- I ning cells 20 will transmit the variouscolor components of the scene toy be televised.V 'I'he coverA plates inthe reproducing cell may also bereplaced by filter plates colored incomplementary colors to correspondto the colors of the filter plates inthe scanning cell.

It will thus be seen that there is provided a system and method by whichthe several objects of this invention are achieved, and which is welladapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention.and as various changes might be made in the embodiments above set forth,it is tov be understood that all matter herein set forth or shown in theaccompanying vlaminar means in said circuit. 1

Iinterference between said circuits.

,a resonant circuit to associate a irequencychardrawings is to beinterpreted as illustrative and not ina limiting sense.

Having thusdescribed my invention, I claim as new and `desire to secureby Letters Patent:

1. A unitary scanning cell adapted to be mechanically moved forscanning, said cell com-- prising a plurality of closely spaced linearlyA aligned electrically insulated elemental photo'-v responsive areas anda plurality of laminar electrical means, each having a characteristicfrequency, each of said areas having 'a different laminar meanselectrically associated therewith,

said laminar means being so connected that the number-of external leadstaken from said'cell for placing all oi said means in an electricaltele- 'vision scanning circuit is no 'greater than the acteristic of itsposition withsaid area, the areas offthe several laminae being linearlyaligned.

7. A unitary. television scanning cell adapted tobe mechanically movedfor scanning, said cell comprising a large number of electricallyinsulated adjacently disposed laminae,| each of said laminae including"a different oscillatory means and an elemental photo-responsive areawhereby a characteristic frequency is associated with each elementalphoto-responsive area, said areas being aligned, a common electrode forsaid areas,A

and means disposed wholly within said cell to electrically connect saidoscillatory means in f parallel whereby the external leads from saidcell number of leads required to, place one of said 2. A unitaryscanning cell adapted to be me chanically moved for scanning, said cellcomprising a pluralityl of closely spaced linearly aligned electricallyinsulated elemental photoresponsive areas and a plurality of laminarelectrical means each having a"v characteristic Irequency, each of saidareas having a different'I laminar means electrically associatedtherewith, each of said laminar means being substantially coplanar withits associated elemental area, said laminar means being so connectedthat the number of external leads taken from said cell yfor placing allof said means in an electrical telel vision scanning circuit is nogreater than the number of ileads 4required to place one of said laminarmeans in said circuit.

3. A` unitary television scanning cell adapted to be'mechanically movedfor scanning, said cell vcomprising a plurality of electricallyinsulated adjacently disposed laminae, each of said lamiare reduced tothe number of leads required to connect but one of said laminae in anelectrical television sending circuit.

8. A unitary television scanning cell adapted to be mechanically movedfor scanning, said cell comprising a large number of electricallyinsulated adjacently disposed laminae, each of .said laminae including adifferent oscillatory means and an elemental photo-responsive areawhereby "a characteristic frequency is associated with each elementalphoto-responsive area, said areasbe- -ing aligned, the diierencebetweenthe characteristic frequency of adjacent laminae 'being greater than thedifference between the characteristic frequency of remote laminae so asto reduce couplingy between adjacent cells, a common electrode for saidareas,i and means disposed vwholly within said cell to electricallyconnect said oscillatory means in parallel whereby the said laminae inan electrical nae including an elemental photo-responsive area in aresonant circuit to associate'airequency characteristic of its positionto said area,-said circuits being connected lin parallel within saidlcell. l 4. A unitary television scanning cell adapted 'to bemechanicallyl moved for scanning, said cell comprising a plurality ofelectrically insulated adjacently disposed laminae, each of saidvlaminae including an elemental photo-responsive area in a resonantcircuit to associate a frequency.-

characteristic, of its position to said area, said circuits beingconnected in parallel within said cell, common means to apply anelectric potential'to said areas, and means intermediate said commonpotential applying means and said areas to prevent interference betweensaid circuits.

5. A unitary television scanning /cellcomprising a plurality oi.'electrically insulated adjacently disposed laminae, each o! said laminaeincluding an elemental photo-responsive area in a resonantv circuit toassociate a frequency 'characteristic of its position tosaid area, saidcircuits being connected in parallel within said cell, common means toapply an electric potential to said areas, and f resistance meansintermediate said common potential 'applying means and ysaid areas toprevent 6. A unitary television scanning cell comprising a plurality ofelectrically insulated adjacently disposed laminae, each of saidlaminaeincluding a pair o! parallel insulated electrically conductive platesforming a capacitance and anat inductance coil interconnecting saidplates','an edge Y oil-enact said-plateshaving a photo-sensitive,

area thereon,Y said coil. and said plates forming external leads fromsaid cell are reduced to the number of leadsy required to connect b utone of television sending circuit. 4 W

9.; A unitary television reproducing cell adapted to b mechanicallymoved for reproducing, said cell comprising a plurality of closelyspaced linearly aligned electrically insulated elemental light-emissivemeans and a plurality of laminar` .electricall means, eachhaving acharacteristic frequency, each of said elemental light-emissive meanshaving a different laminar means electrically associated therewith, saidlaminar means being so connected that the number of external leads takenfrom said cell for placing all of said means in an electric televisionreproducing circuit is vno greater than the number of leads required toplace one of said laminar means in said circuit.

10. A unitary television reproducing 'cell adapt- Q" ciated elementallight-emissive means, said lami nar lmeans being so. connected ,that thenumber of external leads taken from said cell for vplacing all oi' saidmeans in an electric television reproducing circuit isno greater thanthe number of leads required to place onelof said laminar meansl iinsaid circuit.

11. A unitary television reproducing cell adapted 'to be"` mechanicallymoved for reproducing,

'said .cell comprising-a plurality ofielectrically insulated adjacentlydisposed laminae, `each or said laminae including an elementallight-emissive means in a resonant circuittoassociate a y forming aresonant circuitl to'associate a frequency characteristic of itsposition to said lightemissive means, the light-emissive means of theseveral laminae being linearly aligned.

ing a plurality of electrically insulated closely 13. A unitarytelevision reproducing cell adapty ed to be mechanically moved forreproducing, said cell comprising a large number of electricallyinsulated adjacently disposed laminae, each of said laminae including adifferent oscillatory means and an elemental light-emissive meanswhereby a characteristic frequency is associated with eachelementallight-emissive means, said means being'aligned, a commonelectrode for said light-emissive means, and common means disposedwholly Within said cell to energize all of said laminae whereby theexternal leads from said cell are reduced to the number of leadsrequired to connect but one of said laminae in an electrical televisionreceiving circuit.

14. A unitary television reproducing cell adapted to be mechanicallymoved for reproducing, said cell comprising'a large number ofelectrically insulated adjacently disposed laminae, each of said laminaeincluding a different oscillatory means and an elemental light-emissivemeans whereby a characteristic frequency is associated with eachelemental light-emissive'means, said means beingv aligned, thedifference between the characteristic frequency of adjacent laminaebeing greater than the difference between the chara'cteristic frequencyof remote laminae so as to reduce coupling between adjacent cells, acommon electrode for said light-emissive means, and common means'disposed Wholly Within said cell to energize all of said laminae wherebythe external leads from said cell are reduced to the` number of leadsrequired to connect but one of said laminae in an electrical televisionreceiving circuit.

l5. A television transmitting system comprisspaced elementalphoto-responsive areas having a. common circuit and a common feed backto associate different radio frequencies with each of said areas, theamplitudes of each of said radio frequencies being modulated by saidareas in accordance with the light tone value of the correspondingelemental area of the scene being transmitted.

16. A television transmitting circuit comprising a vacuum tube, aplurality of parallel auxiliary circuits of different resonantfrequencies, a plurality of elemental electrically insulatedphoto-responsive areas, 'each of said areas being associated withA oneof said circuits whereby each of said areas is characterized by adifferent frequency, and means to cause said vacuum tube to loscillateat said frequencies, the amplitude of each of lsaid frequencies beingcontrolled by its associated photo-responsive area.

17. A television transmitting circuit comprising a vacuum tube, aplurality of parallel auxiliary circuits of different resonantfrequencies, a plurality of elemental electrically insulatedphoto-responsive areas, each of said areas being associated with one ofsaid circuits whereby each of said areas is characterized by a differentfrequency, means to prevent saidareas from being I Aassociated with anyother than their characterizing frequencies, and means to cause saidvacuum tube to oscillate at said frequencies, the amplitude of each ofsaid frequencies being controlled by its associated photo-responsivearea.

JOHN N. M. HoWELLs.

